Hot water heater with air expelling and cold water mixing arrangement



March 31, 1970 MATARAZZO ET AL 3,503,384

HOT WATER HEATER WITH AIR EXPELLING AND COLD WATER MIXING ARRANGEMENT Filed July 22, 1968 Inc INVENTORS HENRY A'MATARAZZO FRANK R. GIANNELLA AGENT United States Patent 3,503,384 HOT WATER HEATER WITH AIR EXPELLING AND COLD WATER MIXING ARRANGEMENT Henry A. Matarazzo, Bloomfield, and Frank R. Giannella,

Hawthorne, N.J., assignors to Walter Kidde & Cornpany, Inc, Belleville, N.J., a corporation of Delaware Filed July 22, 1968, Ser. No. 746,667 Int. Cl. F24h 1/18, 9/12 U.S. Cl. 126-362 4 Claims ABSTRACT OF THE DISCLOSURE A hot Water heater having a water storage chamber with a cold water inlet at the bottom, a hot water outlet at the top, and a cold water mixing arrangement near the outlet which functions during initial filling of the chamber to expel excess air from the chamber prior to any water flow through the outlet.

BACKGROUND OF THE INVENTION Field of the invention The present invention relates to hot water heaters for domestic purposes and more particularly to such heaters wherein a volume of water is stored at a high temperature and, when a demand is placed on the heater, the high temperature water flowing from the heater is modified by mixing it with cold water.

Description of the prior art It has become common practice in airplanes, trains and house trailers and similar living quarters of limited space to utilize the electric hot water heaters which rapidly heat the water flowing therethrough to reduce or eliminate the need for a bulky storage tank.

In one type of such heaters, a small volume of stored water is heated to a temperature above the desired faucet temperature and a cold water tube extends from the inlet to adjacent the outlet so that, when the faucet is opened and flow commences, this tube introduces cold water which mixes with the hot water at the outlet to bring the water to the desired faucet temperature.

The units of this type available in the past have had a disadvantage in that during initial filling, water would flow from the cold water tube through the outlet together with the air being displaced from the storage volume. As a result, the downstream line would contain alternate slugs of water and air compressed to the pressure of the cold water supply. The faucet used in such systems frequently is provided with a ball-float vent valve to remove air from the line. However, this valve closes when the first slug of water reaches it, and, therefore, additional slugs of compressed air remain in the line between the heater and the faucet. When the faucet is opened for the first time after filling, the back pressure on the slugs of compressed air is released and the air expands, radially propelling the water out through the faucet. The expanding air imparts such speed to the water that it splashes violently when it hits the wash bowl and spatters the clothing of the person operating the faucet.

SUMMARY OF THE INVENTION An object of the present invention is to provide a water heater of the type discussed which is not subject to the foregoing difliculties.

Patented Mar. 31, 1970 Another object is to provide such a heater having a hot and cold water mixing arrangement which functions during initial filling of the heater to prevent water from reaching the heater outlet until all excess air has been expelled from the water storage volume of the heater.

Other and further objects of the invention will be obvious upon an understanding of the illustrative embodiment about to be described, or will be indicated in the appended claims, and various advantages not referred to herein will occur to one skilled in the art upon employment of the invention in practice.

The foregoing objects are generally accomplished by providing in a hot water heater the combination of a water storage chamber, a heating element for heating the water in the chamber, a cold water inlet at the bottom of the chamber, a hot water outlet at the top of the chamber, a flow divider at the inlet providing a flow path into the chamber, a cold Water tube connected to a second flow path provided by the divider and extending vertically within the chamber, the cold water tube being closed off at its upper end and having aperture means in the side wall thereof, and a hot and cold water mixing tube of larger diameter than the cold water tube connected to the outlet and extending vertically downward past the upper end of the cold water tube and surrounding a portion of that tube, the mixing tube being provided with hot water inlet hole means aligned with the aperture means and being substantially larger than the aperture means so that during the initial filling of the chamber water flows from the aperture means in a stream passing the hole means whereby water is prevented from flowing out of the outlet prior to the chamber being filled to the level of the hole means.

BRIEF DESCRIPTION OF THE DRAWING A preferred embodiment of the invention has been chosen for purposes of illustration and description, and is shown in the accompanying drawing, forming a part of the specification, wherein:

FIG. 1 is a longitudinal sectional view of a water heater in accordance with the present invention.

FIG. 2 is an enlarged view of a portion of FIG. 1 illustrating the manner in which the hot and cold water mixing arrangement functions during initial filling of the heater.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawings in detail, there is shown a water heater in accordance with the present invention which generally comprises a water storage tank 10, a plurality of electrical heating elements 11 extending into the tank of which only one is shown, a thermostat 12 extending into the tank for controlling the elements 11, a cold water inlet fitting 14 at the bottom of the tank, a hot water outlet fitting 15 at the top of the tank, a flow divider 16 positioned in the inlet fitting 14, a thin cold water tube 17 connected to the flow divider 16 and extending vertically upward within the tank, and a hot and cold water mixing tube 19 of larger diameter connected to the outlet fitting 15 and extending vertically downward Within the tank. The mixing tube 19 is co-axial with the cold water tube 17 and extends downwardly past the end of the tube 17 to surround the upper portion thereof.

The tank 10 has a cylindrical metal body 20 with top and bottom end caps 21, 22 welded to the ends thereof,

and provides a hot water storage chamber or space 23 having a capacity of approximately two quarts. The heating elements 11 the thermostat 12 extend into the tank through bushings 24 and 25 respectively which are mounted in the bottom end cap 22.

The cold water inlet fitting 14 is welded to the bottom end cap 22 and is of stepped construction to form a large diameter section 27 attached to the end cap 22 and providing a chamber 29, and to form a Smaller diameter coupling section 30 extending from the chamber 29 for connection to a cold water supply line. The hot water outlet fitting 15 is welded to the top end cap 21 and has a threaded coupling section 32 for connection to a pipe leading to a hot water faucet.

The flow divider 16 is positioned in the chamber 29 and is provided with a central passageway 34 and outer passageways 35. The cold water tube 17 is fitted into the passageway 34 and the passageways 35 conduct water from the chamber 29 directly into the storage space 23. A deflector 36 is mounted near the bottom of the cold water tube to direct the inlet flow away from the mixing tube to induce circulation around the heating elements. The cold water tube extends upwardly toward the outlet fitting and has a closed end 37 spaced from the end cap 21 and has one or more apertures 39 in the side wall thereof adjacently below the end 37. The apertures 39 and the passageways 35 are dimensioned so that approximately five volumes of water flow into the tank through the pass-ageways 35 for each volume of water that flows through the apertures 39.

The mixing tube 19 is welded or brazed to the lower end of the outlet fitting 15 and has a closed end 40 provided with an opening 41 through which the cold water tube 17 passes. The tube 19 is provided with one or more holes 42 aligned with the apertures 39 which holes have a substantially larger area than the apertures. The tube 19 is also provided with one or more air vents 44 above the holes 42, and one or more hot water inlet openings 45 and 46 below the holes 42.

In operation, to place the heater in use, the tank is filled to the level indicated by the line W. L. (as described hereinafter) and the heating elements 11 are connected to a source of electrical power. The thermostat 12 is connected into the electrical current line between the elements 11 and the source of electricity to interrupt the flow of current whenever the water in the space 23 reaches a predetermined temperature, for example, about 140 F.

When the hot water faucet downstream of the heater is opened, hot water flows into the mixing tube 19 through the holes 42 and the openings 45 and 46, and cold water flows into the mixing tube through the apertures 39. These flows of hot and cold water mix as they flow into the outlet fitting 15. These flows are proportioned so that the temperature of the water leaving the heater is reduced to between about 105 F. and about 125 F.

Before the heater is initially filled with cold water the space 23 and the water piping leading from the heater to the hot water faucet are filled with air. When the heater is connected to the cold water supply the cold water flows into the space 23 through the passageways 35 and also flows up through the apertures 39.

The holes 42 in the mixing tube 19 are positioned and sized so that the streams of water issuing from the apertures 39 pass through the holes 42 and fall into the space 23 as shown in FIG. 2. This arrangement positively prevents the water flowing out of the cold water tube from being introduced into the downstream line during the initial filling operation. The positioning of the apertures 39 at right angles to the direction of outlet flow, eliminates the possibility of any. direct flow from the col-d water tube into the outlet fitting. The holes 42 eliminate the possibility of the mixing tube being filled prematurely so as to cause water to flow through the outlet before the space 23 is properly filled. The holes 42 also eliminate splashing within the mixing tube by which water could either be deflected toward the outlet or be atomized and entrained with the air which is displaced through the out let fitting as the space 23 fills.

As water flows into the space 23, the air therein is displaced and flows out through the air vents 44 until the water level covers the vents 44 to thereby trap the remaining air within the tank. The water level now rises in the tube 19 and flows out through the fitting 15 as it displaces the air in the downstream piping. In a system which is provided with a ball float vent valve at the faucet,

the air in the line will escape freely through this valve as the water advances. The vent valve will remain open until water enters the valve. Since no water can leave the heater until all of the expellable air has been displaced, all air will have been removed from the downstream line at the time the vent valve closes. Thus, when the faucet is opened for the first time after the space 23 has been filled, a normal steady flow of water will issue from the faucet instead of the erratic spattering flow experienced with the prior heaters.

After'the vent valve has closed, the flow of col-d water into the tank 10 continues until the air trapped within the tank is compressed to a pressure equal to the cold water supply pressure. The air vents 44 are positioned vertically so that the volume of air retained within the tank equals approximately 10% of the total tank volume. This controlled air volume is provided to prevent the tank from bursting should the water therein freeze.

SUMMATION It will be seen from the foregoing description that the present invention provides a hot water heater having a hot and cold water mixing arrangement which funcitons during intial filling of the heater to prevent water from reaching the heater outlet until all excess air has been expelled from the storage volume of the heater.

As various changes may be made in the form, construction and arrangement of the parts herein, without departing from the spirit and scope of the invention, and Without sacrificing any of its advantages, it is to be understood that all matter herein is to be interpreted as illustrative and not in any limiting sense.

We claim:

1. In a hot water heater the combination of a water storage chamber, a heating element for heating the Water in said chamber, a cold water inlet at the bottom of said chamber, a hot water outlet at the top of said chamber, flow dividing means at said inlet providing a flow path into said chamber and a second flow path, a cold water tube in fluid flow communication with said second flow path and extending vertically upward within said chamber, said cold water tube being closed off at its upper end and having aperture means in the side wall thereof, and a hot and cold water mixing tube of larger diameter than said cold water tube connected to said outlet and extending vertically downward from said outlet past the upper end of said cold water tube and surrounding a portion of said cold water tube, said mixing tube being provided with hot water inlet hole means aligned with said aperture means and being substantially larger than said aperture means so that during the initial filling of said chamber water flowing from said aperture means under pressure passes through said hole means in a stream whereby water is prevented from flowing out said outlet prior to said chamber being filled to the level of said hole means.

2. A Water heater according to claim 1, wherein an air vent is provided in said mixing tube above said hole means to allow air within said chamber to readily escape during the initial filling of said chamber.

3. A water heater according to claim 2, wherein said air vent is positioned a sufficient distance below the top of said chamber to cause a volume of air to be entrapped in the top of said chamber.

4. A water heater according to claim 3, wherein hot water inlet opening means are provided in said mixing tube below said hole means.

References Cited UNITED STATES PATENTS 2,294,163 8/1942 Donnelly et a1. 2,592,863 4/ 1952 Conner 126-362 XR 2,600,521 6/1952 Swisher 126362 XR 2,621,901 12/1952 Wheeler 126-362 XR 2,971,532 2/1961 McLaren et al. 3,447,560 6/1969 Dodson et al. 126-362 XR FREDERICK L. MATTESON, JR., Primary Examiner R. A. DUA, Assistant Examiner U.S. Cl. X.R. 137592, 337 

